How do i mock Url object in asp.net mvc

Mock UrlHelper and set the controller's Url property when arranging the test. To mock the request mock the controller's http context and set the controller context.

To demonstrate here is a sample controller based on the provided example above.

public class MyController : Controller {
    [HttpPost]
    public ActionResult MyAction() {
        var link = GenerateActionLink("MyTargetActionName", string.Empty, string.Empty);

        return View((object)link);
    }

    private string GenerateActionLink(string actionName, string token, string username) {
        string validationLink = null;
        if (Request.Url != null) {
            var encodedToken = EncodedUrlParameter(token);
            var url = Url.Action(actionName, "Register", new { Token = encodedToken, Username = username }, Request.Url.Scheme);
            validationLink = url;
        }

        return validationLink;
    }

    private string EncodedUrlParameter(string token) {
        return "Fake encoding";
    }

}

Here is a unit test example that mocks up all the necessary framework dependencies

[TestClass]
public class UrlHelperTest {
    [TestMethod]
    public void MockUrlHelper() {
        //Arrange
        var requestUrl = new Uri("http://myrequesturl");
        var request = Mock.Of<HttpRequestBase>();
        var requestMock = Mock.Get(request);
        requestMock.Setup(m => m.Url).Returns(requestUrl);

        var httpcontext = Mock.Of<HttpContextBase>();
        var httpcontextSetup = Mock.Get(httpcontext);
        httpcontextSetup.Setup(m => m.Request).Returns(request);


        var actionName = "MyTargetActionName";
        var expectedUrl = "http://myfakeactionurl.com";
        var mockUrlHelper = new Mock<UrlHelper>();
        mockUrlHelper
            .Setup(m => m.Action(actionName, "Register", It.IsAny<object>(), It.IsAny<string>()))
            .Returns(expectedUrl)
            .Verifiable();

        var sut = new MyController();
        sut.Url = mockUrlHelper.Object;
        sut.ControllerContext = new ControllerContext {
            Controller = sut,
            HttpContext = httpcontext,
        };

        //Act
        var result = sut.MyAction();

        //Assert
        mockUrlHelper.Verify();
    }
}

So this is my current solution, I ended up constructing the link manually. If there are any better solution please do let me know.

    private string GenerateActionLink(string actionName, string token, string username)
    {
        string validationLink = null;
        if (Request.Url != null)
        {
            var encodedToken = EncodedUrlParameter(token);
            var encodedEmail = EncodedUrlParameter(username);
            var concatenatedUrl =
                $"{Request.Url.Scheme}://{Request.Url.Host}/Register/{actionName}?Token={encodedToken}&Username={encodedEmail}"; 
            validationLink = concatenatedUrl;
        }

        return validationLink;
    }

This way i can still pass in an actionName. If I use the Request.Url, this will always have an action which is usually not what i want to use as stated in my question.